CH3OC(=O)N=C=O
























 





 








Nitrogen


Nuclear Quadrupole Coupling Constants

in Methoxycarbonyl isocyanate

 








 








 








14N nqcc's in methoxycarbonyl isocyanate were determined by Watanabe, et al. [1].  Calculation was made here of the 14N nqcc tensor on ropt molecular structures derived by B3LYP and MP2 optimizations, each with 6-311+G(3df, 3pd) and cc-pVTZ bases (assuming Cs symmetry).  These are compared with the experimental nqcc's in Tables 1 and 2.  Structure parameters are given in Z-matrix format in Table 3.  Rotational constants are compared in Table 4.

 








In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  ETA = (Xxx - Xyy)/Xzz.  

RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD are the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.

 








 








 








Table 1. 14N nqcc's in Methoxycarbonyl isocyanate (MHz).  Calculation was made on  B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) optimized molecular structures.













B3LYP

MP2

Expt [1]

 








Xaa
2.938

2.915

3.0065(11)


Xbb -
1.639
-
1.583
-
1.5949(16)


Xcc -
1.299
-
1.332
-
1.4116(16)


Xab
0.400

0.302




 








RMS

0.080 (4.0 %)

0.070 (3.5 %)




RSD

0.030 (1.3 %)

0.030 (1.3 %)













Xxx -
1.674
-
1.604




Xyy -
1.299 -
1.332




Xcc
2.973

2.936




ETA -
0.126
-
0.0926













 








 








 








Table 2. 14N nqcc's in Methoxycarbonyl isocyanate (MHz).  Calculation was made on  B3LYP/cc-pVTZ and MP2/cc-pVTZ optimized molecular structures.













B3LYP

MP2

Expt [1]

 








Xaa
2.930

2.902

3.0065(11)


Xbb -
1.632
-
1.567
-
1.5949(16)


Xcc -
1.298
-
1.335
-
1.4116(16)


Xab
0.407

0.295




 








RMS

0.082 (4.1 %)

0.076 (3.8 %)




RSD

0.030 (1.3 %)

0.030 (1.3 %)













Xxx -
1.668
-
1.586




Xyy -
1.298 -
1.335




Xcc
2.966

2.922




ETA -
0.125
-
0.0858













 








 
 


Table 3.  Methoxycarbonyl isocyanate.  B3LYP and MP2 optimized structure parameters.  ( and degrees).
 



 C
 O,1,B1
 O,1,B2,2,A1
 C,3,B3,1,A2,2,D1,0
 H,4,B4,3,A3,1,D2,0
 H,4,B5,3,A4,1,D3,0
 H,4,B6,3,A5,1,D4,0
 N,1,B7,2,A6,3,D5,0
 C,8,B8,1,A7,2,D6,0
 O,9,B9,8,A8,1,D7,0






B3LYP/6-311+G(3df,3pd)
MP2/6-311+G(3df,3pd)





 B1=1.20074617
 B2=1.33136798
 B3=1.43853165
 B4=1.08443229
 B5=1.08756812
 B6=1.08756812
 B7=1.39985645
 B8=1.21352279
 B9=1.1570087
 A1=125.83891612
 A2=115.37320554
 A3=105.3010063
 A4=110.30504932
 A5=110.30504932
 A6=125.52634517
 A7=130.38307006
 A8=173.40247177
 D1=0.
 D2=180.
 D3=-60.49409536
 D4=60.49409536
 D5=180.
 D6=0.
 D7=180.
 B1=1.20483808
 B2=1.32984078
 B3=1.43510142
 B4=1.08281736
 B5=1.08615369
 B6=1.08615369
 B7=1.40111711
 B8=1.22317328
 B9=1.16453118
 A1=125.92119334
 A2=113.66143936
 A3=105.18929025
 A4=110.14314415
 A5=110.14314415
 A6=125.96335352
 A7=127.29781355
 A8=172.6860178
 D1=0.
 D2=180.
 D3=-60.42725385
 D4=60.42725385
 D5=180.
 D6=0.
 D7=180.






B3LYP/cc-pVTZ
MP2/cc-pVTZ





 B1=1.2015855
 B2=1.33320587
 B3=1.43920613
 B4=1.08497014
 B5=1.08813488
 B6=1.08813488
 B7=1.40088299
 B8=1.21347221
 B9=1.15865206
 A1=125.93973902
 A2=115.11433537
 A3=105.29295321
 A4=110.38122347
 A5=110.38122347
 A6=125.61412059
 A7=130.46024813
 A8=173.35515661
 D1=0.
 D2=180.
 D3=-60.47812035
 D4=60.47812035
 D5=180.
 D6=0.
 D7=180.
 B1=1.2060757
 B2=1.33310738
 B3=1.4365205
 B4=1.08292259
 B5=1.0861393
 B6=1.0861393
 B7=1.40262854
 B8=1.22423117
 B9=1.16718231
 A1=125.97056539
 A2=113.22345475
 A3=105.25629338
 A4=110.30516028
 A5=110.30516028
 A6=126.08227138
 A7=126.7170313
 A8=172.52027378
 D1=0.
 D2=180.
 D3=-60.43839514
 D4=60.43839514
 D5=180.
 D6=0.
 D7=180.








 














Table 4.  Methoxycarbonyl isocyanate.  Rotational Constants (MHz). 





6-311+G(3df,3pd) B3LYP/
 MP2/
    Expt [1]






A
 11087. 11049.
11041.67903(37)

B
  1392.   1391.
  1417.838077(66)

C
  1247.   1245.
  1266.547230(87)





cc-pVTZ
B3LYP/  MP2/






A
 11052.
11014.


B
   1409.
  1411.


C
   1260.
  1260.




 









 









[1] S.Watanabe, Y.Kawashima, and N.Kuze, Abstract ML06, 73rd ISMS, Champaign-Urbana, Illinois, 2018.


 









 








HNCO

CH3NCO CH3CH2NCO t-(CH3)3CNCO


 








 









Table of Contents





Molecules/Nitrogen




 








 













CH3OCONCO.html






Last Modified 18 Nov 2018